• Childhood Kidney Diseases
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• v.18 no.1
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• pp.42-46
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• 2014

Kawasaki disease (KD) is a systemic vasculitis that can affect many organ systems. Renal manifestations include pyuria, hematuria, proteinuria, tubulointerstitial nephritis, acute renal failure, hemolytic uremic syndrome, or renal scarring. Although its precise pathogenesis remains unknown, it is considered an autoimmune disease. In the literature, it has been reported that KD may develop in conjunction with urinary tract infections. However, many of these previous studies did not use imaging methods such as renal sonograms, dimercaptosuccinic acid renal scans, and voiding urethrocystograms. We report a case of an 8-month old male infant with high grade vesicoureteral reflux, who developed incomplete KD after recurrent pyelonephritis. Acute pyelonephritis can be an early manifestation of KD. Such cases require the evaluation of urinary tract anomalies according to the guidelines for the management of urinary tract infections.

• Childhood Kidney Diseases
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• v.1 no.1
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• pp.53-59
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• 1997

There have been many recent reports that unilateral renal agenesis and multicystic dysplastic kidneys are accompanied by contralateral vesicoureteral reflux leading to its injury. We grouped the children with unilateral renal agenesis, renal hypoplasia, multicystic dysplastic kidney into abnormal unilateral renal development and investigated whether it was accompanied with contralateral vesicoureteral reflux. We retrospectively reviewed 96 pediatric cases of unilateral renal agenesis, hypoplasia, multicystic dysplastic kidney diagnosed at Shinchon Severance Hospital, Yongdong Severance Hospital from 1987 to 1996 and Ajou University Hospital from 1994 to 1996. Diagnosis was based on radiological findings, renal hypoplasia being defined as small renal size with no apparent renal scarring and no irregularity of the calyceopelvic system on abdominal sonography or intravenous pyelography. Among the 96 cases,48 cases carried out voiding cystourethrography. 58 cases were male(60%) and 38 cases were female(40%). The cases of abnormal unilateral development on the left side were 45(47%) and that on the right side were 51(53%). Although there were diverse reasons leading to diagnosis, the major ones included were prenatal sonography, urinary tract infection, and other congenital anomalies. In cases of unilateral renal agenesis & hypoplasia the leading factors were urinary tract infection & other congenital anomalies and in cases of multicystic dysplastic kidney that was prenatal sonography. There was a chronological gap between the mean age of diagnosis(1.8 year) and voiding cystouerthrography(2.5 year, P < 0.01). 9 of the 18 unilateral renal agenesis cases, 5 of the 11 unilateral renal hypoplasia cases, and 3 of the 19 unilateral multicystic dysplastic kidney cases showed contralateral vesicoureteral reflux. Average reflux grade was above G III.Among the 17 children who had contralateral vesicoureteral reflux, 3 children had chronic renal failure and ureteroneocystostomy was carried out in 6 children. From the above results we conclude that screening voiding cystourethrography should be performed in children with abnormal unilateral renal development for early detection of vesicoureteral reflux in the contralateral kidney.

• Investigative Magnetic Resonance Imaging
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• v.4 no.2
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• pp.85-93
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• 2000

Purpose: To evaluate the availability of magnetic resonance (MRI voiding cystography for the diagnosis of vesicoureteral reflux (VUR) and to compare the sensitivity of MR voiding cystography (MRVC) with that of radiographic voiding cystourethrography (VCUG) in the detection of VUR. Material and Methods : MRVC was performed upon 20 children referred for investigation of VUR. Either coronal T1-weighted spin-echo or spoiled gradient-echo images were obtained before and after transurethral administration of a mixture of normal saline and gadopentetate dimeglumine, and immediately after voiding. The findings of MRVC were compared with those of VCUG performed within 6 months of MRVC. Results 1 VUR was detected in 23 ureterorenal units f16 VUR's by both methods, five VUR's by VCUG, and two VUR's by MRVC). The sensitivity of VCUG and MRVC in detecting VUR was 91.3% (21/23) and 78.3% (18/23), respectively. MRVC detected renal scarring in 15 out of 17 kidneys with scintigraphically detected renal scarring. Conclusion : Although MRVC is slightly less sensitive than VCUG in the detection of VUR, it can be used for the diagnosis of VUR and renal scarring simultaneouslyl and thus will reduce the radiation hazard.

• Clinical and Experimental Pediatrics
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• v.45 no.12
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• pp.1540-1545
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• 2002

Purpose : Vesicoureteral reflux(VUR) is defined as a retrograde flow of urine from the bladder into the upper urinary tract. It has been shown to predispose patients to hypertension, renal scarring, and end-stage renal failure if not recognized and treated. The observation that VUR occurs in siblings of children with reflux at a significantly higher rate than the general pediatric population has been recognized for many years and VUR was detected in 26% to 51% of siblings of patients with VUR. The purpose of this study is to determine the incidence of VUR in asymptomatic siblings of children with VUR and to see if this form of screening would be practical. Methods : We retrospectively reviewed the records of 28 patients with VUR and their siblings. The total number of asymptomatic siblings investigating VUR were 28 persons. All patients and siblings were evaluated for VUR by a voiding cystourethrography and all patients and siblings with VUR were performed $^{99m}Tc$ 2,3-dimercaptosuccinic acid renal scan. Results : A total of 28 patients(14 boys, 14 girls) with VUR were studied; the mean patient age was 2.7 years(range 1 month to 8.4 years). The total number of asymptomatic siblings investigating VUR were 28 persons(17 boys, 11 girls) and the mean age was 3.3 years(range 2 months to 7.4 years). Renal scar was detected in 20 of 28(71.4%) patients with VUR. VUR was noted in three of 28(10.7%) siblings and renal scar was detected in one of three siblings with VUR. Conclusion : In this study, the predictive value of a positive family history alone in identifying VUR was 10.7%. This incidence suggests more investigation of asymptomatic siblings and continued study of this group of patients at risk is needed for clarifying the family screening of patients with VUR.

• Childhood Kidney Diseases
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• v.14 no.1
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• pp.71-78
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• 2010

Purpose : Hydronephrosis is found about 30% of children with urinary tract infection (UTI). It can be caused by various conditions, although most childhood hydronephrosis is congenital. This study was performed to investigate the relationship between febrile UTI and hydronephrosis. Methods : We retrospectively reviewed the medical charts of 183 patients diagnosed as UTI between January 2007 and May 2009 at Korea University Guro Hospital. Inclusion criteria were as followings; 1) fever more than $37.5^{\circ}C$ measured in the axilla, 2) positive urine culture, 3) no history of urinary tract anomaly on antenatal sonography and urinary tract infection. We classified the enrolled children into two groups of patients with hydronephrosis (HN) and those without hydronephrosis (NHN). Results : The 80 patients were HN and 103 patients NHN. Hydronephrosis was found in 58 patients with left kidney, 8 right and 14 both kidneys. Most of hydronephrosis were of low grade. Compared with NHN group, initial renal cortical defects on DMSA scan significantly increased in HN group (HN 37.5%, NHN 16.5%, P<0.05). The incidence of VUR was not different between the two groups (HN 22%, NHN 12.1%). White blood cell counts and C-reactive protein were not different between the two groups. Follow-up DMSA scan (about 6 months later after UTI) showed no difference of renal scarring in both two groups. Conclusion : Our data suggests that hydronephrosis in febrile UTI patients is clinically useful for detecting renal cortical defects, but is not associated with follow-up renal scar.

• Childhood Kidney Diseases
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• v.11 no.1
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• pp.24-31
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• 2007

Purpose : Nitric oxide(NO) is a very potent vasodilator synthesized from L-arginine by endothelial cells. We investigated whether urinary NO excretion was altered in various renal diseases in children and whether urinary NO excretion could be used in predicting pathologic causes and fibrosis in renal diseases in children. Methods : We recruited 48 patients(32 minimal change nephrotic syndrome[MCNS] and 16 vesicoureteral reflux[VUR] patients from the pediatric renal clinic in Korea University Guro Hospital. We measured the concentration of nitrite$(NO_2)$ and nitrate$(NO_3)$ by Griess reaction and that of creatinine(Cr) by Jaffe method in randomized spot urines. We then analyzed the urinary$(NO_2+NO_3)/Cr$ ratios and compared the values between each patient group. Urinary $(NO_2+NO_3)/Cr$ ratios were also evaluated according to the recurrence and the degree of proteinuria at sampling in the MCNS group and compared according to the presence of renal scarring and the grade of reflux in the VUR group. Results : The ratios of urinary$(NO_2+NO_3)/Cr$ were significantly increased in the VUR and MCNS groups, as compared to the control group. In the MCNS group, a higher level of urine $(NO_2+NO_3)/Cr$ was observed In frequent relapse patients(relapse over four times within one year after first diagnosis) and the patients with severe proteinuria at sampling, respectively. The VUR group with renal scars also showed a higher level of urinary$(NO_2+NO_3)/Cr$ compared to that without scars. Conclusions : In summary, VUR may play a role in the pathogenesis of VUR and MCNS. NO also seems to affect proteinuria and renal scar formation. (J Korean Soc Pediatr Nephrol 2007;11:24-31)

• Childhood Kidney Diseases
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• v.12 no.1
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• pp.62-69
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• 2008

Purpose: The most concerning issue in children with urinary tract infection(UTI) is the probability of underlying genitourinary anomalies and vesicoureteral reflux (VUR), which is frequently associated with renal scarring and eventually end-stage renal disease. Therefore, voiding cystourethrography(VCUG) is usually recommended at the earliest convenient time for children with UTI. However, VCUG is an invasive procedure that requires catheterization and exposure to X-ray. In this study, we aimed to determine the predictability of clinical, laboratory and imaging parameters for VUR in children with UTI. Methods: Data of children with bacteriologically proven UTI who underwent VCUG were evaluated retrospectively for clinical(age, gender, fever), laboratory(leukocytosis, ESR, CRP, pyuria, blood urea nitrogen, serum creatinine) and imaging(renal ultrasound and DMSA renal scan) findings. First, children with UTI were divided into two groups according to the presence of VUR as non-VUR group and with VUR group, and clinical, laboratory variables were compared between these groups. Second, patients who had VUR were reclassified as low-grade VUR(grade I-II) group and high-grade(grade III-V) VUR group according to grading of VUR, and clinical, laboratory and imaging variables were compared between these groups. Results: Among 410 children with UTI, 137 had VUR and 78 high-grade VUR. Fever, leukocytosis, ESR, CRP, pyuria were associated with VUR. In addition, abnormal findings of ultrasonography and DMSA renal scan were closely related to VUR. However, these clinical and laboratory variable in patients with high grade VUR were not different significantly, compared to those with low-grade VUR group. Conclusion: Fever, leukocytosis, ESR, CRP seems to be potentially useful predictors of VUR in pediatric patients with UTI. In addition, renal ultrasonography and DMSA renal scan findings supported the presence of VUR. Further study of these findings could limit unnecessary VCUG in patients with UTI.

• Childhood Kidney Diseases
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• v.9 no.1
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• pp.46-55
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• 2005

Purpose : Recurrent urinary tract Infection(UTI) in primary vesicoureteral reflux(VUR) may lead to serious renal scarring, a major cause of childhood hypertension and end-stage renal disease. To prevent recurrent UTI, low-dose long--term antibiotic prophylaxis has been recommended. However, recurrent UTI still develops during antibiotic prophylaxis, the efficacy of which is now being disputed. The emergence of resistant bacteria has also raised concerns. To evaluate the effect of antibiotic prophylaxis, we investigated recurrent UTI during prophylactic antibiotic use in children with primary VUR Materials : The incidence and risk factors of recurrent UTI were retrospectively evaluated in ninety-one children with primary VUR on trimethoprim- sulfamethoxazole(TMP/SMX) prophylafis during the year following their index febri]e UTI. Results : Recurrent UTI occurred in 31.9%(29/91) children and comprised 0.32 episodes/patient year. Febrile UTI was 0.26 episode/patient year and afebrile UTI was 0.07 episodes/patient year. The recurrent rate of UTI in male patients with phimosis was 37.2%(19/51), which was significantly higher than in males without phimosis 0%(0/5)(P=0.025). In the logistic regression analysis for recurrent UTI, renal scar was the significant risk factor for recurrent UTI [RR 3.8(95% CI 1.0-14.1) P=0.04]. For other well-known risk factors such as sex, age, degree of VUR, APN, and voiding dysfunction, the differences were not significant. Conclusion : TMP/SMX prophylaxis did not prevent recurrent UTI in children with primary VUR. Phimosis and renal scars were the risk factors for recurrent UTI but the grade of primary VUR was not. In VUR without phlmosis and renal scar, a randomized controlled study without antibiotic prophylaxis is required. (J Korean Soc Pediatr Nephrol 2005;9:46-55)

• Childhood Kidney Diseases
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• v.21 no.1
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• pp.15-20
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• 2017

Purpose: Febrile urinary tract infection (UTI) is one of the commonest bacterial infections in children. The purpose of this study is to investigate the clinical characteristics of the first episode of febrile UTI occurring in children over 5 years compared to those in infants younger than a year. Methods: We retrospectively reviewed the medical records of 10 patients over 5 years, having febrile UTI, and 25 controls under 1 year. Clinical characteristics including symptoms at admission, the time interval between symptom onset and hospital visit and/or diagnosis, duration of fever, urinalysis, and other laboratory and imaging test results were compared between the two groups. Results: Most patients in the control group showed only high fever at the time of presentation to the hospital. However, 60% of the case group had fever along with gastrointestinal (GI) symptoms such as abdominal and flank pain, vomiting, as well as relatively mild pyuria. The case group showed a longer duration between symptom onset and hospital visit and/or diagnosis. Conclusions: Delay in diagnosis and initiation of treatment of UTI increases the risk of permanent renal scarring and associated complications. Therefore, early diagnosis and treatment of febrile UTI is vital for very young infants, as well as children considering that febrile UTI could be an important cause of febrile illness in children over 5 years.

• Clinical and Experimental Pediatrics
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• v.59 no.3
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• pp.139-144
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• 2016

Purpose: Acute pyelonephritis (APN) is a serious bacterial infection that can cause renal scarring in children. Early identification of APN is critical to improve treatment outcomes. The neutrophil-lymphocyte ratio (NLR) is a prognostic marker of many diseases, but it has not yet been established in urinary tract infection (UTI). The aim of this study was to determine whether NLR is a useful marker to predict APN or vesicoureteral reflux (VUR). Methods: We retrospectively evaluated 298 pediatric patients ($age{\leq}36months$) with febrile UTI from January 2010 to December 2014. Conventional infection markers (white blood cell [WBC] count, erythrocyte sedimentation rate [ESR], C-reactive protein [CRP]), and NLR were measured. Results: WBC, CRP, ESR, and NLR were higher in APN than in lower UTI (P<0.001). Multiple logistic regression analyses showed that NLR was a predictive factor for positive dimercaptosuccinic acid (DMSA) defects (P<0.001). The area under the receiver operating characteristic (ROC) curve was high for NLR (P<0.001) as well as CRP (P<0.001) for prediction of DMSA defects. NLR showed the highest area under the ROC curve for diagnosis of VUR (P<0.001). Conclusion: NLR can be used as a diagnostic marker of APN with DMSA defect, showing better results than those of conventional markers for VUR prediction.